To frolic is to play without a reason. Not to exercise, not to unwind, not to network at the company picnic — to move, or laugh, or chase, or splash, because the body found itself with energy and nowhere serious to put it. Lambs frolic. Puppies frolic. Children, given a few minutes unsupervised near water, frolic. Adults, mostly, have to be reminded that the option still exists.
The word is a loan and a reshape. It comes from the Dutch vrolijk — "merry, cheerful" — cousin to German fröhlich, and ultimately to an old Germanic root meaning "glad" or "quick-spirited." English borrowed it in the sixteenth century, first as an adjective meaning simply joyous, and only later as the verb and noun we use now. The ancestor describes a state of mind; the descendant describes what that state of mind makes the body do.
The missing k
The older spelling was frolick, with a final k. It was everywhere in the seventeenth and eighteenth centuries, then quietly lost its consonant in the nineteenth, together with musick, publick, logick, and a whole small graveyard of other -ick words. Samuel Johnson's dictionary (1755) still kept the k; Noah Webster, a generation later, was already pruning it. The k was not doing any phonetic work — frolic and frolick sound the same — so it went the way of silent letters that nobody was emotionally attached to.
A few writers still miss the older form. The k gave the word a small visible kick, a little flick of the heel at the end, which is not the worst thing for a verb about skipping around. Modern dictionaries list frolic as the standard and frolick as an archaism. The standard won because print tends to reward economy; the archaism survives in pastiche and period writing, where its age is the point.
What it protects
English has plenty of serious words for enjoying yourself: recreation, leisure, entertainment, all of them vaguely clinical, each carrying a faint scent of scheduling. Frolic resists all of that. You cannot frolic on a timetable. You cannot frolic for something. The moment an activity has a target — fitness, bonding, content creation — it stops being a frolic and becomes an outing.
That is the small thing the word protects. Not joy in general, which is a big category, but joy with no destination. The particular kind of pleasure that does not survive being optimised. Every few months, on a good afternoon, it is worth remembering that the option still has a name.